books.google.com - The U.S. took in more than a million immigrants per year in the late 1990s, more than at any other time in history. For humanitarian and many other reasons, this may be good news. But as George Borjas shows in Heaven's Door, it's decidedly mixed news for the American economy--and positively bad news...https://books.google.com/books/about/Heaven_s_Door.html?id=3r0HkiNoqAMC&q=human+capital&utm_source=gb-gplus-shareHeaven's Door